Brake construction



Oct. 20, 1953 R. LAPSLEY BRAKE CONSTRUCTION Filed May 10, 1951 FIG. I

M QW 00 0609090 P0 l I 0 0 0 6 0 0 3 s Q 9 6 Q VIII/Il v M I INVENTOR.ROBERT LAPSLEY BY Q 4 ATTYS.

Patented Oct. 20, 1953 BRAKE CONSTRUCTION Robert Lapsley, Buchanan,Mich., assignor to Clark Equipment Company, Buchanan, Mich., acorporation of Michigan Application May 10, 1951, Serial No. 225,642

2 Claims.

My invention relates generally to brakes, and, more specifically, isdirected to a self energizing brake construction operable for braking arotating drum.

It is an object of my present invention to provide a rotating drum, and,which in addition, efiects controlled rotation of the brake drum in anormal direction of rotation of the drum immediately prior to completerelease of the brake drum for rotation.

The present brake construction has utility, for example, in atransmission of the character disclosed in my copending applicationSerial No. 283,176, filed April 19, 1952. In this transmission the brakedrum forms part of a ring gear of a planetary gear assembly which ringgear is adapted to be clutched to a shaft by means of an axiallyshiftable clutch collar member. The clutch collar member is formed withsuitable jaw clutch teeth which are adapted to be selectively disposedin engagement with jaw clutch teeth associated with the ring gear. Afterthe brake band of the brake construction has been applied to the ringgear for braking the latter, it frequently happens that the jaw clutchteeth of the clutch collar member are mis-aligned relative to the jawclutch teeth of the ring gear and thus engagement of the clutch teeth isimpossible. In order to permit engagement of the jaw clutch teeth, Ihave provided a brake construction which will effect controlled rotationof the brake band and ring gear in a normal direction of rotation of thering gear immediately prior to complete release of the band from brakingengagement with the ring gear. This controlled rotation permits the jawclutch teeth of the clutch collar member to be snapped into engagementwith the jaw clutch teeth of the ring gear after which the ring gear mayrotate in its normal manner.

The brake construction for accomplishing the above object comprises abrake band encircling the ring gear and having adjacent free ends.Spring means is associated with one 01- the ends for normally biasingthe latter toward the other end of the brake band. Means, which in thespecific embodiment of my invention comprises fluid actuated means, isassociated with the other end of the brake band and is adapted whenactuated to urge the other end of the brake band toward the one endagainst the force of the Spring means whereby the brake band iscontracted for braking the ring gear. The deflection of the spring meanswill cause the brake band assembly to rotate a controlled amountopposite to the normal direction of the brake drum rotation. Uponrelease of the fluid actuated means, the spring means simultaneouslyefiects controlled rotation of the brake band and ring gear in normaldirection of rotation of the ring gear immediately prior to completerelease of the band from braking engagement with the ring gear. It willbe understood that the brake construction of my present invention hasutility with brake drums other than in the form of ring gears, thisillustration being given by way of exemplification and not limitation.

Now, in order to acquaint those skilled in the art with the manner ofconstructing and using the device of my present invention, I shalldescribe in connection with the accompanying drawing, a preferredembodiment of my invention.

In the drawing:

Figure 1 is a vertical sectional view of the brake construction of mypresent invention.

Referring now to the drawing, there is shown a brake drum In which, may,for example, form part of a ring gear of a planetary assembly as isshown in detail in my copending application Serial No. 283,176, filedApril 19, 1952. Disposed adjacent the brake drum I0 is a housing memberii which has a cylindrical portion [2 closed at its lower end. Mountedfor reciprocating movement within the cylinder portion i2 is a pistonit. A fluid chamber 9 is formed between the piston i3 and the closed endof the cylindrical portion 12. The piston i3 is formed with a centralopening M which receives the generally spherically shaped lower end 8 ofa vertically extending rod member IS. The rod member i5 intermediate orits ends projects through a central opening it formed in a member Hwhich is maintained in the cylindrical portion i2 by means of aretaining ring I8 suitably mounted in the cylindrical portion [2.

A spring carrier 19 is disposed about the rod member at adjacent itslower end and downward movement of the spring carrier [9 relative to therod member i5 is limited by a retaining ring 20 secured in the rodmember I5. A spring 2| is disposed concentrically about the rod memberit. The upper end of the spring 2i abuts against member I! and at itslower end abuts against the spring carrier [9. The spring 2! normallybiases the rod member #5 together with the piston is to the positionshown in Figure 1.

The upper end of the rod member 25 has secured thereto a pin member 22on which is secured the one end of a brake band 23 which encircles thebrake drum 10. Also pivotally mounted to the pin member 22 is the oneend of a lever 24. The other end of the lever 24 is pivotally mounted at25 to a plate member 26 end 30 of a rod member 3|. The axis of rodmember 3| is substantially aligned with the axis of the rod; member l5,A spring carrier 32 is disposed concentrically about the rod membercover member 28 and at their lower ends abut the spring carrier 32 fornormally biasing the rod member 3| downwardly as viewed in Figure 1.

The lower end of the rod member 3|; has secured therein a pin member 35upon which is mounted the other end of, the aforementioned brake handv2.3. Also pi'votally mounted on the pin member 35 is the one endof. alever 36. The other end of the lever. 38.is pivotally mounted at, 3.1 tothe aforementioned platemember 2B.

A pin member 38 issuitably mounted in. the plate member 26, and, is.adapted to. provide a stop for the lever 35.. it willthusbe seenthatdownward movementof the rod member. 3| islimited. by the. engagementoithe. lever 36 with the pin member 38 asshown in Figural.

With the various elements of the brake as sembly disposed in thepositionshewntin. Figure 1, the brake band: 23. is. in a released ornonbraking position and; thetbrake'drum 19. is free to rotate; Upon the.selective admission of'iiuid under pressure to the..-chamber 9-the-piston [3,

together; with the rodmember l5, forced. up-

wardly which places a counterclockwise tension on the, brake; band; 23.causing the latter to: be: applied tothe, bralredrum N If the brakedrum. I; is rotating in-.-. clockwise direction as indicated. by thearr.ow,- the counterclockwise tension on; the brake bandg 23; willincrease as the latter initially engages theedrum. l-fl, since the band23 will tend to rotate opposite'the drum- H). It will, thus. be;apparent; that the brak construction is selfeenergizing in one,directionof rotation and increases the ability of the springs Bettebrake. the drum l m.

A plurality of springs are dis-' posed concentrically about the rodmember 3|., The springs 34 at their upper ends abut the bers I and 3|permit limited pivotal movement of the rod members l5 and 3| duringmovement of the: latter when the brake. band 2 3 is applied to the drum.H) or released therefrom.

Now, while I have shown and described what I- believe to be a preferredembodiment of my invention, it will be understood that various Thecounterclockwise;tension; applied to: the;

brake band 23:willcause the rod member's-i tore d unwar -ly: agai st hdownwa dlr iasing force; of-the plurality of;springs.34.-' which;

in turn causes the cran stiaim3fi totbeerotatedg clockwise from the;positiom showrrin ;Eigi1re.; 1 o a; position. nutt f ontactawiththe:nin- -1K1? ber 38.

Iffluid; under pressure is now bled. from the;

fluid chamber. 9, the; piston I;3.=,; together; with; the rod member1.5,. willbe: urged: downwardly; under the biasing. force ofispringrzl,WhiChzWill finally: release the counterclockwise 1361151011 1. on; the:

brake band 23; Simultaneously;,the dOWHWZJIfir 1y biasing force: or the.plurality of; springs: 39'- and the rotativerforcemfnduuml l 0; willurge: he:

rod member 31 downwardly until-thecranharm 36 engages the pin: member.-38..' During. this, downward movement of the:rod,member;-3i,r a,clockwise rotationis appliedstothe brake bands. 23 which causescontrolled rotationof. thesbrakew drum It! in aclockwise directionimmediately prior to complete release of the. band 23: from.- brakingengagement with the drum i=0, After the brake band 23 has beeniullyreleased; from engagement with the brake..- dr-um. I:l1, the elements ofthe brake. construction'assume the-position shown in Figure 1. and thedrum H):- is;

again free to rotate Thespherical ends-8: and 3.0: at. the-rod: meme:

modifications and rearrangements may be made there-in without departingfrom the spirit and scope of my invention.

11 claim:

1. Brake means comprising a brake drum, a brake'band'encirel ing saiddrum and having adjacent 'free ends, a pair of levers pivotally mountedat their one ends one to each of the saidfree endsof said band, saidlevers at their other ends having fixed pivotal anchors, a pair ofsubstantially aligned" rod" members" pivotally mounted at their one endsone" to" each of the" said freev ends of. said band, springm'eans-associated with one of' said rod' members for-normally biasing the lattertoward the: other of saidtrod members',, and means associated with theother of said rod memberwhi'ch means, is adapted when actuated" to urgethe said" other rod member toward the said one rodmem-ber against theforce ofisai'd'spring meansxwhereby said brake band is contractedifor'braking said drum and rotating the lattera controlled amount:

in a direction opposite tothenormal direction of rotation. of saidbrakedrum.

2. Brake means comprising. a brake drums brake band. encircling. saiddrum. andihaving" adjacent free ends, a h0using,.- a pair offlever's'piv' otally mounted at their oneend's one to eacnof the said free endsof? said". band; said. l'ever'ls at their other ends being pivotallyfmounted to. said",

housing, apair. of. rod members pivotallyniouri at, their one endsrone;to each. of the sardines ends of said band, coil spring, meansdisposed".

concentrically about one of; said rodi'members' between the. latter andsaid housing for. Iio'rmally. biasing the saidfone, rod member toward.

the other of, said rod. members, stop. means: car: ried by said housing.for limiting movenrentof said. one rod, member toward said'othen' rodmember, fluid pressure actuatedlmeansiassbci'e ated with the other of;said rod membersjwhioli... meansvis adapted whenactuat'ed to urge. thesaid I other rod member. toward. the said one. rod mem ber against, theforce of said coil spring. means. whereby the; latten is partiallycompressed 1 and said. brake band is contracted. for braking, said?drumiand rotating. thelattera controlled amount-Z."

in a direction opposite tothe normal direction of. rotation ofsaid-brake. drum and said". coil. spring means when saidlfliiidpress'ureactuatedi means is released being, adapted. to expand" wherebysaid. band. and. said d'rum arerotatedla controlled amountin the .inormal. direction of rotation. of said-drum immediatelyprioryto, com'-plete release; of said band frombrakin'g'j enga esment with-saidl drum.

